1. Field of the Invention
The present invention pertains to an interface system for use in providing a flow of pressurized gas to a patient, and, in particular, to an interface system having a manually actuated valve structured to selectively impede the flow of pressurized gas to the patient. The invention also relates to a conduit having such a valve and to a method of providing a flow of pressurized gas to a patient using such a valve.
2. Description of the Related Art
There are numerous situations where it is necessary or desirable to deliver a pressurized flow of breathing gas non-invasively to the airway of a patient, i.e., without intubating the patient or surgically inserting a tracheal tube in the esophagus. For example, it is known to ventilate a patient using a technique known as non-invasive ventilation. It is also known to deliver continuous positive airway pressure (CPAP) or variable airway pressure, such as a bi-level pressure that varies with the patient's respiratory cycle or an auto-titrating pressure that varies with the monitored condition of the patient. Typical pressure support therapies are provided to treat a medical disorder, such as sleep apnea syndrome, in particular, obstructive sleep apnea (OSA), or congestive heart failure.
During such treatments, a supply of pressurized gas is typically supplied to a patient through a patient interface, such as a nasal, oral, or combination nasal/oral mask. While wearing such an interface that is providing pressure, a patient commonly experiences difficulty speaking. Such difficulty generally occurs most dramatically in nasal masks, but is also a problem in full face mask applications, commonly used to treat obstructive sleep apnea. In such instances, as a person attempts to speak, they must fight the pressure and flow of the gas supply. This causes the patient's voice to become distorted, which is a major inconvenience to the user. If a person attempts to remove the mask as they speak, they risk changing or losing the seal as they re-apply the mask. Noise also generally increases in mask removal as the machine (typically CPAP) ramps up flow in an attempt to reach nominal pressure, without resistance. To stop the flow, and speak comfortably, the user must shut off the machine, which could be located an inconvenient distance away.